Cycles: Support half and half4 textures.

This is an initial commit for half texture support in Cycles.
It adds the basic infrastructure inside of the ImageManager and support for these textures on CPU.

Supported:
* Half Float OpenEXR images (can be used for e.g HDRs or Normalmaps) now use 1/2 the memory, when loaded via disk (OIIO).

ToDo:
Various things like support for inbuilt half textures, GPU... will come later, step by step.

Part of my GSoC 2016.

2 files changed, 41 insertions, 4 deletions

diff --git a/intern/cycles/util/util_half.h b/intern/cycles/util/util_half.h
index f4bac9888a5..ae85ab3a915 100644
--- a/intern/cycles/util/util_half.h
+++ b/intern/cycles/util/util_half.h
@@ -85,6 +85,27 @@ ccl_device_inline void float4_store_half(half *h, float4 f, float scale)
 #endif
 }
 
+ccl_device_inline float half_to_float(half h)
+{
+	float f;
+
+	*((int*) &f) = ((h & 0x8000) << 16) | (((h & 0x7c00) + 0x1C000) << 13) | ((h & 0x03FF) << 13);
+
+	return f;
+}
+
+ccl_device_inline float4 half4_to_float4(half4 h)
+{
+	float4 f;
+
+	f.x = half_to_float(h.x);
+	f.y = half_to_float(h.y);
+	f.z = half_to_float(h.z);
+	f.w = half_to_float(h.w);
+
+	return f;
+}
+
 #endif
 
 #endif
diff --git a/intern/cycles/util/util_texture.h b/intern/cycles/util/util_texture.h
index e00edc046f7..2ef47283029 100644
--- a/intern/cycles/util/util_texture.h
+++ b/intern/cycles/util/util_texture.h
@@ -26,40 +26,56 @@ CCL_NAMESPACE_BEGIN
 #define TEX_NUM_BYTE4_CPU		1024
 #define TEX_NUM_FLOAT_CPU		1024
 #define TEX_NUM_BYTE_CPU		1024
+#define TEX_NUM_HALF4_CPU		1024
+#define TEX_NUM_HALF_CPU		1024
 #define TEX_START_FLOAT4_CPU	0
 #define TEX_START_BYTE4_CPU		TEX_NUM_FLOAT4_CPU
 #define TEX_START_FLOAT_CPU		(TEX_NUM_FLOAT4_CPU + TEX_NUM_BYTE4_CPU)
-#define TEX_START_BYTE_CPU		(TEX_NUM_FLOAT4_CPU + TEX_NUM_BYTE4_CPU + TEX_NUM_BYTE_CPU)
+#define TEX_START_BYTE_CPU		(TEX_NUM_FLOAT4_CPU + TEX_NUM_BYTE4_CPU + TEX_NUM_FLOAT_CPU)
+#define TEX_START_HALF4_CPU		(TEX_NUM_FLOAT4_CPU + TEX_NUM_BYTE4_CPU + TEX_NUM_FLOAT_CPU + TEX_NUM_BYTE_CPU)
+#define TEX_START_HALF_CPU		(TEX_NUM_FLOAT4_CPU + TEX_NUM_BYTE4_CPU + TEX_NUM_FLOAT_CPU + TEX_NUM_BYTE_CPU + TEX_NUM_HALF4_CPU)
 
 /* CUDA (Geforce 4xx and 5xx) */
 #define TEX_NUM_FLOAT4_CUDA		5
 #define TEX_NUM_BYTE4_CUDA		88
 #define TEX_NUM_FLOAT_CUDA		0
 #define TEX_NUM_BYTE_CUDA		0
+#define TEX_NUM_HALF4_CUDA		0
+#define TEX_NUM_HALF_CUDA		0
 #define TEX_START_FLOAT4_CUDA	0
 #define TEX_START_BYTE4_CUDA	TEX_NUM_FLOAT4_CUDA
 #define TEX_START_FLOAT_CUDA	(TEX_NUM_FLOAT4_CUDA + TEX_NUM_BYTE4_CUDA)
-#define TEX_START_BYTE_CUDA		(TEX_NUM_FLOAT4_CUDA + TEX_NUM_BYTE4_CUDA + TEX_NUM_BYTE_CUDA)
+#define TEX_START_BYTE_CUDA		(TEX_NUM_FLOAT4_CUDA + TEX_NUM_BYTE4_CUDA + TEX_NUM_FLOAT_CUDA)
+#define TEX_START_HALF4_CUDA	(TEX_NUM_FLOAT4_CUDA + TEX_NUM_BYTE4_CUDA + TEX_NUM_FLOAT_CUDA + TEX_NUM_BYTE_CUDA)
+#define TEX_START_HALF_CUDA		(TEX_NUM_FLOAT4_CUDA + TEX_NUM_BYTE4_CUDA + TEX_NUM_FLOAT_CUDA + TEX_NUM_BYTE_CUDA + TEX_NUM_HALF4_CUDA)
 
 /* CUDA (Kepler, Geforce 6xx and above) */
 #define TEX_NUM_FLOAT4_CUDA_KEPLER		1024
 #define TEX_NUM_BYTE4_CUDA_KEPLER		1024
 #define TEX_NUM_FLOAT_CUDA_KEPLER		1024
 #define TEX_NUM_BYTE_CUDA_KEPLER		1024
+#define TEX_NUM_HALF4_CUDA_KEPLER		0
+#define TEX_NUM_HALF_CUDA_KEPLER		0
 #define TEX_START_FLOAT4_CUDA_KEPLER	0
 #define TEX_START_BYTE4_CUDA_KEPLER		TEX_NUM_FLOAT4_CUDA_KEPLER
 #define TEX_START_FLOAT_CUDA_KEPLER		(TEX_NUM_FLOAT4_CUDA_KEPLER + TEX_NUM_BYTE4_CUDA_KEPLER)
-#define TEX_START_BYTE_CUDA_KEPLER		(TEX_NUM_FLOAT4_CUDA_KEPLER + TEX_NUM_BYTE4_CUDA_KEPLER + TEX_NUM_BYTE_CUDA_KEPLER)
+#define TEX_START_BYTE_CUDA_KEPLER		(TEX_NUM_FLOAT4_CUDA_KEPLER + TEX_NUM_BYTE4_CUDA_KEPLER + TEX_NUM_FLOAT_CUDA_KEPLER)
+#define TEX_START_HALF4_CUDA_KEPLER		(TEX_NUM_FLOAT4_CUDA_KEPLER + TEX_NUM_BYTE4_CUDA_KEPLER + TEX_NUM_FLOAT_CUDA_KEPLER + TEX_NUM_BYTE_CUDA_KEPLER)
+#define TEX_START_HALF_CUDA_KEPLER		(TEX_NUM_FLOAT4_CUDA_KEPLER + TEX_NUM_BYTE4_CUDA_KEPLER + TEX_NUM_FLOAT_CUDA_KEPLER + TEX_NUM_BYTE_CUDA_KEPLER + TEX_NUM_HALF4_CUDA_KEPLER)
 
 /* OpenCL */
 #define TEX_NUM_FLOAT4_OPENCL	1024
 #define TEX_NUM_BYTE4_OPENCL	1024
 #define TEX_NUM_FLOAT_OPENCL	0
 #define TEX_NUM_BYTE_OPENCL		0
+#define TEX_NUM_HALF4_OPENCL	0
+#define TEX_NUM_HALF_OPENCL		0
 #define TEX_START_FLOAT4_OPENCL	0
 #define TEX_START_BYTE4_OPENCL	TEX_NUM_FLOAT4_OPENCL
 #define TEX_START_FLOAT_OPENCL	(TEX_NUM_FLOAT4_OPENCL + TEX_NUM_BYTE4_OPENCL)
-#define TEX_START_BYTE_OPENCL	(TEX_NUM_FLOAT4_OPENCL + TEX_NUM_BYTE4_OPENCL + TEX_NUM_BYTE_OPENCL)
+#define TEX_START_BYTE_OPENCL	(TEX_NUM_FLOAT4_OPENCL + TEX_NUM_BYTE4_OPENCL + TEX_NUM_FLOAT_OPENCL)
+#define TEX_START_HALF4_OPENCL	(TEX_NUM_FLOAT4_OPENCL + TEX_NUM_BYTE4_OPENCL + TEX_NUM_FLOAT_OPENCL + TEX_NUM_BYTE_OPENCL)
+#define TEX_START_HALF_OPENCL	(TEX_NUM_FLOAT4_OPENCL + TEX_NUM_BYTE4_OPENCL + TEX_NUM_FLOAT_OPENCL + TEX_NUM_BYTE_OPENCL + TEX_NUM_HALF4_OPENCL)
 
 
 /* Color to use when textures are not found. */